scholarly journals Microstructure Design and Its Effect on Mechanical Properties in Gamma Titanium Aluminides

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1644
Author(s):  
Xuqi Liu ◽  
Qia Lin ◽  
Wenjing Zhang ◽  
Constance Van Horne ◽  
Limei Cha
Keyword(s):  
Mechanical Properties ◽  
Titanium Aluminides ◽  
Turbine Blades ◽  
Strengthening Mechanism ◽  
Engineering Properties ◽  
Processing Technologies ◽  
Tial Alloys ◽  
Gamma Titanium ◽  
Fundamental Information ◽  
Gamma Titanium Aluminides

Intermetallic gamma titanium aluminides display attractive engineering properties at high temperatures of up to 750 °C. To date, they have been used in low-pressure turbine blades and turbocharger rotors in advanced aircraft and automotive engines. This review summarizes the fundamental information of the Ti–Al system. After providing the development of TiAl alloys, typical phases, microstructures and their characteristics in TiAl alloys, the paper focuses on the effects of alloying elements on the phase boundary shifting, stabilizing effects and strengthening mechanism. The relationships between chemical additions, microstructure evolution and mechanical properties of the alloy are discussed. In parallel, the processing technologies and the common heat treatment methods are described in detail, both of which are applied to optimize the mechanical properties via adjusting microstructures. On this basis, the effects from chemical composition, processing technologies and heat treatments on microstructure, which controls the mechanical properties, can be obtained. It has a certain guiding significance for tailoring the microstructures to gain desired mechanical properties.

The Use of In Situ Characterization Techniques for the Development of Intermetallic Titanium Aluminides

2014 ◽  
Vol 783-786 ◽  
pp. 2097-2102 ◽  
Author(s):  
Svea Mayer ◽  
Emanuel Schwaighofer ◽  
Martin Schloffer ◽  
Helmut Clemens
Keyword(s):  
Titanium Aluminides ◽  
Turbine Blades ◽  
Heat Treatments ◽  
Mechanical Processing ◽  
Tial Alloys ◽  
Solidification Processes ◽  
Consistent Picture ◽  
Aero Engines ◽  
Multi Phase

Urgent needs concerning energy efficiency and environmental politics require novel approaches to materials design. One recent example is thereby the implementation of light-weight intermetallic titanium aluminides as structural materials for the application in turbine blades of aero-engines as well as in turbocharger turbine wheels for the next generation of automotive engines. Each production process leads to specific microstructures which can be altered and optimized by thermo-mechanical processing and / or subsequent heat-treatments. To develop sound and sustainable processing routes, knowledge on solidification processes and phase transformation sequences in advanced TiAl alloys is fundamental. Therefore, in-situ diffraction techniques employing synchrotron radiation and neutrons were used for establishing phase fraction diagrams, investigating advanced heat-treatments as well as for optimizing thermo-mechanical processing. Summarizing all results a consistent picture regarding microstructure formation and its impact on mechanical properties in advanced multi-phase TiAl alloys can be given.

Effect of hydrogen on the elastic modulus and hardness of gamma titanium aluminides

1999 ◽  
Vol 41 (8) ◽  
pp. 839-845 ◽  
Author(s):  
P.A. Sundaram ◽  
D. Basu ◽  
R.W. Steinbrech ◽  
P.J. Ennis ◽  
W.J. Quadakkers ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Titanium Aluminides ◽  
Gamma Titanium ◽  
Gamma Titanium Aluminides

Determination of the diffusion coefficient of hydrogen in gamma titanium aluminides during electrolytic charging

2000 ◽  
Vol 48 (5) ◽  
pp. 1005-1019 ◽  
Author(s):  
P.A. Sundaram ◽  
E. Wessel ◽  
H. Clemens ◽  
H. Kestler ◽  
P.J. Ennis ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Titanium Aluminides ◽  
Gamma Titanium ◽  
Gamma Titanium Aluminides

Studies on Ductile Damage and Flow Instabilities during Hot Deformation of a Multiphase γ-TiAl Alloy

2014 ◽  
Vol 611-612 ◽  
pp. 99-105 ◽  
Author(s):  
Dilek Halici ◽  
Hassan Adrian Zamani ◽  
Daniel Prodinger ◽  
Cecilia Poletti ◽  
Daniel Huber ◽  
...  
Keyword(s):  
Hot Deformation ◽  
Titanium Aluminide ◽  
Titanium Aluminides ◽  
Turbine Blades ◽  
Shear Bands ◽  
Flow Instabilities ◽  
Ductile Damage ◽  
Gamma Titanium Aluminide ◽  
Gamma Titanium ◽  
Damage Models

Gamma titanium aluminides are promising alloys for low-pressure turbine blades. A significant disadvantage of such intermetallic alloys is failure induced during forming processes due to ductile damage and flow instabilities. Previous investigations on a gamma titanium aluminide alloy (TNM), have shown ductile damage due to tensile stress components and instabilities such as shear bands, pores and micro-cracks at low temperatures and high strain rates. The main part of the current work is to delineate damage and unstable regions in the low temperature region. Hot deformation experiments are conducted on a Gleeble®3800 thermomechanical treatment simulator to obtain flow curves to be implemented in a finite element method (FEM) code. Instabilities in the material are described by existing instability criteria as proposed by Semiatin and Jonas and implemented into FEM code DEFORMTM 2D. Predictions of ductile damage models and the instability parameter are validated through detailed microstructural studies of deformed specimens analysed by light optical- and scanning electron microscopy.

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